Celestial happenings you can see from your own backyard

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Cool auroras possible this hot July weekend

The stars of the Big Dipper (left) contrast with the soft rays and arc of the aurora early on the morning of July 10, 2013. Credit: Bob King

You sure can tell the sun’s been busy. Little more than a year ago I rarely made mention of the northern lights. We’d just experienced what felt like an eternal solar minimum. For months on end there were no sunspots and the solar storms or flares they produce. That meant few if any opportunities to see the northern lights from the peopled latitudes of southern Canada, the U.S. and Europe.

Now it seems like every few days the aurora’s in the forecast. I fear I sound like a broken record, but interest in auroras is high and I’d be remiss to not mention an opportunity to see them.

Late tonight through Saturday night, the NOAA space weather forecastcalls for minor aurora storms brought on by another coronal mass ejection from the sun. Right now, Saturday night looks best. I’ll be watching the reports and will update the blog as needed.

NASA Solar Cycle 24 sunspot number prediction as of July 2013. The previous solar max – Cycle 23 – was in March 2000. Credit: NASA

Solar cycles last anywhere from 9 to 14 years with the average being 11. During a typical cycle the sun gradually peaks in activity with lots of spots and stormy weather followed by a decline to solar minimum, when our star barely utters a peep.

19th century German astronomer Heinrich Schwabe discovered the sunspot cycle almost by accident. He was searching for the hypothetical planet Vulcan believed at the time to circle the sun within the orbit of Mercury. While Schwabe watched for Vulcan’s tiny black silhouette to pass in front of the sun, he noticed that the number of sunspots waxed and waned over a period of roughly 11 years.

Heinrich Schwabe (SCHVA-bay), right, discovered the sunspot cycle while Rudolf Wolf (left) went back over historical observations to trace the cycle back in time. Credit: Wikipedia

Swiss astronomer Rudolf Wolf was mightily impressed with Schwabe’s discovery and researched the historical record to compile a list of cycles all the way back to the first sunspot observations by none other than Galileo. Wolf’s numbering theme begins with Cycle 1 which spanned from 1755-1766. The current cycle is number 24 and it’s peaking this summer and early fall. Overall this cycle has been a dud, the lowest solar max since Cycle 14 in 1906. Still, we’ll take it. Compared to the deep minimum of 2008-2010 it feels like fireworks.

About astrobob

My name is Bob King and I work at the Duluth News Tribune in Duluth, Minn. as a photographer and photo editor. I'm also an amateur astronomer and have been keen on the sky since age 11. My modest credentials include membership in the American Association of Variable Star Observers (AAVSO) where I'm a regular contributor, International Meteorite Collectors Assn. and Arrowhead Astronomical Society. I also teach community education astronomy classes at our local planetarium.

Sorry to cuss, but looks like it will be cloudy to partly cloudy for us tonight.
For the past few weeks though, Ive been on a positive streak during this 2nd double peak on actually being home for the lights, and cloud free…for the most part.
Im hoping when the big one hits one of these months, it will all come together as smoothly.
I hope you get the chance tonight Bob and others who are reading this.